Ovum Pick Up (OPU) and In Vitro Maturation (IVM)

When handling oocytes, temperature and pH fluctuations should be minimised. Therefore it is recommended to use incubators,  heated stages and plates to warm all medium and consumables. We recommend these items should be calibrated to 38.5°C.

Using an appropriately buffered medium will limit pH fluctuations which is why we have designed our entire media suite to have exceptional pH stability due to the combination of buffers that we use. We also have transport maturation media options that can be used without the requirement of gas during in vitro maturation (IVM). Transporting gas cylinders across the country can be logistically challenging so ask us about our alternatives to suit your requirements!

It is also recommended to use consumables that are embryo safe and non-toxic. Bovine embryos are more sensitive than mouse embryos therefore performing Bovine Embryo Assays are recommended instead of Mouse Embryo Assays for testing toxicity of plasticware and mediums used for in vitro production of bovine embryos.

When searching and selecting for cumulus oocyte complexes (COCs) they should be selected based on evenly coloured cytoplasms and a complete layer of cumulus cells as a minimum (although sometimes there is no choice based on the quality of COCs/oocytes collected). An important tip is to wash COCs thoroughly in order to remove blood and excess granulosa cells following OPU and before transporting them back to the laboratory in IVM media.  Each step of COC/oocyte collection and IVM is critical to setting up successful fertilisation and embryo production, contact us at admin@artlabsolutions.com to discuss how we can maximise your cattle breeding opportunities.

Ovum Pick Up (OPU) vs Multiple Ovulation Embryo Transfer (MOET)

There are many advantages and disadvantages to choosing the right method of embryo production for your cattle as both technologies have their place.

A few highlights of performing OPU on your donors can save both time and money. OPU does not utilise any hormone injections, thus minimising cost, and can be replicated as regularly as every 4 days. Whereas MOET requires bringing donors into the yards twice per day, for 3 or 4 days in a row which can be quite laborious, especially in a centre managing several programs over consecutive days.

Furthermore, OPU-IVF allows for excellent semen economy. The same straw of semen can often be used over hundreds of oocytes from multiple donors. Another advantage is that if there are large numbers of oocytes collected, they can also be split and fertilised by more than one bull in vitro.

If you would like to have a chat about OPU-IVF procedures, please contact our team directly at admin@artlabsolutions.com for more information.

The risks we take – an IVF story.

Most who work in the cattle IVF field as a commercial enterprise are, in some way or other, challenged every day.  However, some situations are so challenging, they are worthy of a story to be told.

An Australian Wagyu breeder enlisted a team consisting of an experienced cattle ART vet, IVF and genetics leaders, including ourselves and SpeedBreed, Gnarwarre (near Geelong, Victoria, Australia), to deliver as many calves as possible from just two straws of semen.  The genetics within those two straws was of such high value that each straw cost tens-of-thousands of Australian dollars.  And to complicate things further, we had no idea how the semen would perform under IVF conditions!  This was a BIG investment by the breeder – it had to work.  The first decision that carried a risk was to cut one straw in half, use one half for the first day’s collection and the other for a 2nd day’s collection.

Although the OPU went well on the first day of collection (29 donor cows, providing 284 good quality COCs), and the transport maturation looked fine, there were fewer cleaved embryos than expected following IVF (51%). It gave, what we would categorise as a poor, but by no means uncommon result from untested semen.  As a result, good quality embryo number was also lower than expected (56, 38% of cleaved), but this is also a characteristic of poor fertilisation.  We suspected the issue was a not-optimized IVF step.  The sperm motility was fine, but we know some bulls that have good AI fertility may be poor at IVF.  We agreed to increase the heparin level, to twice our normal dose.  This was a further risk, but we needed to boost IVF rates.  It was worth it, as the cleavage rate was 75% of COCs (304 from the same 29 cows), and good quality embryo production from cleaved was just below 60% (135 embryos).  For OPU-derived oocytes, this is at the upper end of the spectrum.

We are now awaiting the pregnancy outcomes, but this story is about the need to adjust practices, evaluating the risks and making decisions that really impact IVF success.